Long-term effects of galantamine treatment on brain functional activities as measured by PET in Alzheimer's disease patients

Abstract

The effects of galantamine (16 to 24 mg/day) treatment on brain functional activities (blood flow and glucose metabolism) were examined in 18 patients with mild Alzheimer's disease (AD) in relation to brain acetylcholinesterase (AChE) activity and nicotinic receptors and cognitive function. The study consisted of an initial double-blind phase of three months (short-term) followed by an open-label phase until twelve months after the beginning of the study (long-term). The AD patients underwent positron emission tomography (PET) studies with the tracers [15O]-H2O for measurement of regional cerebral blood flow (rCBF) at baseline, 3 weeks, 3 and 12 months treatment, and [18F]-fluoro-deoxyglucose (FDG) for measurement of regional cerebral metabolic rate for glucose (rCMRglc) at baseline and 12 months. A battery of neuropsychological assessments was performed on each patient in order to follow changes in cognition during the treatment period. Throughout the study, different cortical areas showed significant increases in rCBF after galantamine treatment. rCBF positively correlated with AChE activity, nicotinic receptors and cognition. In addition to these positive changes, an increase in rCMRglc in the frontal brain region and stabilization in other cortical areas was observed after 12 months galantamine treatment. This stabilization in rCMRglc was also correlated with a stabilization of cognition. Our results ultimately suggest that treatment with galantamine has a long-term positive effect on brain perfusion and rCMRglc and stabilizes cognition.